Add badges to Project Migration

What does this MR do and why?

Related to #339416 (closed)

⚠ this feature is behind bulk_import_projects feature flag that is currently off by default (and disabled on .com).

This MR adds Project Badges migration when using Group Migration that includes projects (https://docs.gitlab.com/ee/user/group/import/).

This MR also updates existing badges pipeline to be used in for both groups and project migrations.

Screenshots or screen recordings

projectbadges

How to set up and validate locally

1. Feature.enable(:bulk_import).
2. Feature.enable(:bulk_import_projects).
3. Create a top level group and project in it.
4. Create project and group badges in both group and project.
5. Go to /groups/new#import-group-pane page and enter instance url and access token (needs to be api & read_repository scope).
6. Select newly created group and click Import.
7. Wait for Group import to complete and verify imported badges. No duplicates should be created.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.